Clutch mechanism



April 25, 1933. R. G. GRIFFITH CLUTCH MECHANISM Filed Aug. 14, 1951 INVE NTOR RONALD G. GRIFFITH 'AT EY Patented Apr. 25,1933

"UNITED TATES PATENT oFFicE if RONALD GEORGE GRI'FFITI oF CROYDON, ENGLAND; Ass IGNoR TO cn'nnn lmnf CIOM- 2 leANY, LIMITED, or onoYnoN, ENGLAND @[cLU'reH MECHANISM A puae n filed aug st 14,1931, serial no.

This invention relates to mechanism as used in conjunction with selecting mechanism forsetti-ngla rotatable type he'adin any 7 one of a number of positi ns;

i In printing-telegraph apparatus to whlch the invention is applicable, for instance, a selecting mechanism operating under C011? trol of received signals-is adapted to actu ate one of a number of stop members cir cularly arranged and cooperating with a rotatable type-head which carries a number of type characters corresponding to the stop members. The rotatable type head is rotated by a source of mechanical power and on selection and actuation" of one of the stop members is arrested in a position at which a type character corresponding to that stop is opposite aprinting hammer,

In printlngapparatus of this class the rotatable type-head is usually driven from the source ofmechanioal power through a yielding frictioncluteh and an arm orother stop portion on: the driven member ofthe clutch to which the type is attached, is adapted'to engage the selected stop member and thus effect the arrest of the type-head; the friction clutchyilding whilst the typehead is maintained in 'theselected position. At high speeds of operation when the typehead is repeatedly released for rotation and re-arrested at different positions, the" yielding friction clutch must transmit suflicient power to enable the type-head rapidly to acquire its rotary motion towards the next position on each release. Under these conditions considerable shock occurs ateach arrest of the type-head causing rapid wear and tear, and also rebound andfchatter of the type-head atthe instantwhen printing is required tobe effected, causingirregular and incorrect printing. l

The object ofgthe present invention is to provide an improved clutch mechanism;

for rotatable type-heads in cases of this nature whereby the shock and rebound on arrest of the rotating portion is considerably reduced. f

According to a mainfeature, a rotatable: type-head clutch mechanism comprises a rotatable driving member a type-head frici gages with a stop member 557 ,i083, and in. Great Britain July 2,1931

tionally driven bythe drivingmeniber and havinga number of'i type {characters ar-' ranged thereon, a series of stat onary stop members corresponding to theltype characters and a yielding stop-arm carried .by the type-head and engageable' with an actuated one of the series of stop members. For the purpose of the present invention, the yield? ing stop arm servesas' a cushioning inem:

ber between the type-headand' the series of stop members. Thestop-arm itself maybe formed as a springmember amples hereinafter 'shownastop-arm is provided rotatable with thetype means is providedin combination with the member and engagement; therewith of the yielding arm, the type-head continuesto head but COIL-I A but in the ex; 5

nected thereto througlia separate spring member. 7 i in q According to a second feature, latching advance slightly and thelatchin'gmeans en-I corresponding to thearrested' position and ward movement of the type-head.

, A further feature consists of forming the frictional driving means in the form of a prevents any back-- coil clutch, and a spring arm for arresting.-

the typehead as above described ,i'szalso adapted toefi'eot a, reduction of the frictional driving force between the drivingand driven members of the, coil clutch; l In the accompanying drawing, Figs-.1,

2 and 3 show a rotatable type-head clutch mechanism embodyingall. the features of the invention, each figureshowingthe various parts in different relative position. Figs. 4 andl5 show amend-view of latching 1 means more clearly; Fig.6 shows an experspective Tof ja type-head v and, clutch assembly in which assembly the ar means is formed as ai'plainploded tional driving friction clutch. ,c a

Referring to Figs. 1 to 5;inclusive, shaped driving memberl 'is rotated 2 by a source oflmechanical power ((1 1012 shown). I with this driving member 1 is a stationar series of selectable stop members 3, eac

95. on axis.

.Situated around andconcentric member on selection being independently as shown by member 3A. Independently rotatable on axis '2 is a rotatable type-head (not shown) to Which arm 4 is attached,

Which type-head carries a circular. series of type characters corresponding to the series I type bars carried thereon, may be used; a

' i The type-head j arm 4 is -driven trom the driving' niember of the clntchby a' coiled" spring band/5 attached at oneend 6Ito' the j e a purpose hereinafter to be describechthe of stop members 3'. The arrangement of the series of stop members for arresting the type. head in; any one of a number p of positions isvvell known. Anyconvenient'means:

maybe employed for selecting and actuating the stop'members, and anyform of typehead: such as a type-wheel, or a type-carrier having a number of independently movable typerhead; arm t andshaped as shown for coiled spring band 5 being adapted to make frictional contact with "the inner periphery of, the driving member 11. independently .niovableon axis& is a stop larmfi connected tothe'type-head arm 4 by a curved spring blade 8 which isadapted normally to main tain stoparm 7 in advance of type-h'eada'rnr 4Qin=the direction of rotation; suitable means i beingprovided-'to. liinit the ;rir oti( )i'1j.ofarm Trelativelyto arm 4;" As Willhereinaftei, appear, inthearrangement shown iniFigs 'i -llto ov, the spring 'blade' 8ofitself. is adapted to -serve this" purpose and other functions; The direction of rotation with the arrange ment aspshown in'the drawingisContraEi clockwise as indicated by the arrovv, andithe, coiled spring. 5 normally tends to drive the;

type-head arm 'in this direction; When a v stop members has'beenselected, it is interl posed in the path o'faltooth 9 onlthestopl arm 7 The shock of arresting the typeheadis considerably reduced as energy absorbed "in straining. spring. blade '8. By su tably proportioningthe, strength of the colled sp'ringfband 5 supplying the frictional driving power and that of the spring banda'actuatingstop arm 7 the frictional driving force canbe arranged to be just sufliient to carry" the 'type-head' arm 4 up to aposition in which abutting faces 10 and driving force. on coiledspring 5.

' jplac-e. on arrest of the rotating movement to 11; on the stop arm and type-head arm re spectively, positionithe type-head for'the print ng of the selected j'oharacter, in' which; posltlon it is *maintainedfby the" frictional.

"In order to ensure that no rebound takes" cause incorrect positioning, the type headjis shovvn-iu-Figs; 1lto 5 by a hooked spring preferably, arranged withfilatching means,

i catch member fixe dto the type head arm 'an'd normally revolving clear of the ends of theQstop men lbers A member' fixed to 'stoparm' has a bent caln portion Iii-Which of catch member 12.f On arrest of the stop 7 V co-operates with the. hooked springportion 'niovable in aradialldirection to a posltion arm by a'stop memb-er o the type-h'ead/arm 4 continues to advance as previously de-- scribed, and just before coming to rest the catch member 12' engages Withthe' cam pore tion 13 and is latched behind a stop member corresponding to itsarrested position, in this case shown as the actuated stop member 8A; The normal'jfposition. during] rota tion; ofthetype-head' is shown in, Figs. '1'

and 4:, the" position in the arrested condition selected stop member returnsto its normal This Withdraws thecam} portion .13"from.; the

being shown in Figs. 2 and; 5. "When" the i latch member 12,'which:thereuponiis' freeto rotate clear of the sto .membfers,

The coiledspringband as previously mentioned; isl preferably "shaped asshown inJFigsl 1 c0113.Theband is attaclied at 6 1v" half .a turn-following the internal; con

. to thetype-headiarrn jhima-kesl approx imatetion'oi'rotation, is then bent in towards the axis '2 'forga' furtherportion of mum and then aga n, pens out and forms approximerely a three-quarter turn around the outside of the previous {portions and with the outer surface of the band forming a fricg tional-driving surfaceincontaot with the internali'surface of the. driving member '1' The inbent pOrtionof thefcoiled -band Sis adapted to engagewith thefflspring 'blflde 8 of stop arm/Z. when the.lattenisireleased and .the 'typehead. is rotating; thismeans the; motion of {thestop arm in ad vance of the type-headzis limitedas previ-v k 9. r 8 on coiled spring band 5 serves to. inerease I the frictional driving. force between the" I two friction clutclrmembers1and,5; v "When" ously. referred" to a'ndthe pressure of blade the 's toparm. 7 is arrested, the. springblade' 8 "is. drawn clear of the; cOiled'springband 5'. as-shown in :Fig. 2 andet'he driving force oftlie clutch is reduced. The .eoiled spring; i

5 formed inthe shape as describedl is .oar-

ried round still further by the frictional contact with driving melnberfl in the directioniofrotation to aposition. substantially as shown in Fig. 3,;and .in this, condition 7 V the driving force ofgthe clutch inthe arrestedposition, of the type-head is consider ablyred uc'ed'.

Fig. 6 shows a modified construetion: ini. v which shock absorbing meansis employed 'With'a plain disc type of friction clutch,

but in- ,Which the latching meansf is shown as a 'C'shaped flat spring 14; arranged eoncentric fvviththefaxis-of rotation of the clutch and fixedat both ends to thefdriven I member 15 of the. clutch, theldriving memher being representedby the disc 16pressed. i

against the driven membergbyl the threearmed sprin 17 retained in place by block 18 on the drlving shaft. A stop arm member 19, loosely mounted on a sleeve 20'0f the driven member 15 is connected to .the latter by spring 21 attached by the ends thereof to suitable pins 22 and 23 on the stop arm member 19 and driven member 15, respectively, so asto maintain thesto arm member normally in a position in a vance of the driven member. A. tooth 24 on the stop arm member 19 is adapted to engage a selected stop member 3' as already described and the motion of the stop arm member 19 relatively to that of the driven member 15 is limited by projections 25 and 26 on the latter member; the directionof rotation of the clutch being contraclockwise as before. The stop arm member 19 also carries a cam projection 27 which is adapted to engage a cam plate 28.fixed to the mid-portion of the C spring '14:, when thestop arm is in the advanced position relatively to the driven member. By this means alatching projection 29, also fixed to the mid-portion of the C spring 145, is maintained clear of the ends of the stop'member 3 when the type head is being rotated by the clutch, but when the stop arm member 19 is arrested by a selected stop member the driven member 15 continues to advance, the

s rin 21 bein strained in so doin so as b b b to cushion the arrest of a type carrier which arrest is efiected by projection 26 on the driven member abutting the stop arm member and in this position of the driven member the cam plate 28 fixed to the C spring 14 is carried beyond the cam projection 27 on the stop' arm member. The latching projection, 29 is thus left free to be actuated slightly in an axial direction by the (1 ber, a type-head having a numberof type characters arranged thereon and friction ally driven by said driving member, a stationary series of selectable stop memberscorresponding to said type characters, a yielding stop arm carried by said'type-head and engageable with an actuated one of saidseries of stop members, and means controlled by the stop arm and rendered effective by the engagement thereof with an actuated stop member to reduce the frictional driving contact between the driving member and the type-head.

2; rotatable type-head clutch mechanism'comprising, a rotatabledriving. member,a,-type-head havingja number of type characters arranged thereon and, frictionally dri cven by .said driving member, a stationary, series of [selectable @stop members corresponding to said type characters, a stop arm independently movable ,on the axis of rotation of said, driving member and. en-- gageablewith an actuated; one of saidxse riesof stop members, L and a'xspring tending to maintain lsaldvstop arm 1n .a- POSltlOIL 1n ,7

advancev of said lty-pe' head in; the direction ofjrotationp i :3. ,A- rotatable type-head siestanism comprising, a cup-shaped drivingmem ber, q-a typekhead having a :number of type characters arranged thereon, a stationary series of stopgmembers, acoiled spring-band attached at i one end to. said type=head =and frictionally engaging with the internal surf face 'of' said driving member, and 'a yield: ing stop arm carried-by said type-head: and

engageableqwith an actuated one of said series of stop members a 5 v Al. :Al rotatableatype-head clutch mechanism comprising, a lrot'atablej cup-shaped? driving member, a type-head having a numberi of-stypetcharactrsularranged thereon, af 1 stationary series of stop -members, a coiled spring band attached at one end to said typehead and frictionally engaging with the inner surface of said driving meih r, a stop arm independently movableon the axis of rotation of said driving member and engageable with an actuated one'of said series ofstop members, and a spring tending to maintain said stop arm in a position in advance or saidtype-head in the direction of rotation.

5. A rotatable type-head clutch mechanism comprising, a rotatable cup-shaped driving member, a type-head having a number of type characters arranged thereon, a

coiled spring band attached at one end to said type-head frictionally engaging with the internal surface "ofsaid driving member, a stationary series of selectable i stop members corresponding. to said type characters, an arm independently movable on the axis of rotation of'said driving member, and a curveduspring blade tending to maintain the; stop armin a positionlin ad- I Vance of said typehead and adapted inthis positionto bear on the inner surface of said colled spring band for increasing the frictional driving. contact during. rotation by ran-f said driving member and on arrest of said stop arm to withdraw andreduce the frictional driving contact thereof. a i j V '6. A, rotatable type-head clutch mecha-' nism comprising,xa rotatable, driving member, a type-head having a number oftype characters arranged thereon, a stationary series of selectable stop members corre- DISOLAI MER 1,905,090.R0nald George Grifith, Croydon, England. CLUTCH MECHANISM.

Patent dated April 25, 1933. Disclaimer filed October 11, 1934, by the assignee, Creed and Company, Limited.

Hereby enters this disclaimer to that part of claim 2 which is in the following words, to wit:

A rotatable type-head clutch mechanism comprising, a rotatable driving member, a type-head having a number of type characters arranged thereon and frictionally driven by said driving member, a stationary series of selectable stop members corresponding to said type characters, a stop arm independently movable on the axis of rotation of said driving member and engageable with an actuated one of said series of stop members, and a spring tending to maintain said stop arm in a position in advance of said type head in the direction of rotation.

[Ofict'al Gazette October 80, 1984.] 

